Drill bit head



' 1941- H. E. WILLIAMS 2,252,745

DRILL BIT HEAD Filed Jan. 10, 11939 INVE/V TOR, B/jowmu E. WILL Patented Aug. 19 i941 UNITE D I STATES PATENT OFFICE lloward E. Application January 10, 1939, Serial No. 250,1 1 Claim.- (oi. 255-03) 'Ihis' invention relates to a arm head for use particularly in the drilling of rock or the like,

for the purpose or placing explosive charges in the drilled holes, whereby sections of the rocky structure are broken up for various uses.

My drill head is particularly useful in connection with a percussiontype oi. tool, such. as a pneumatic hammer rotary drill and the like.

An object of my invention is to provide a novel drill head provided with replaceable blades which can be quickly and easily removed and rearranged in the drill head, thereby'enabling said head to retain its proper gauge and enabling the workman to progress further with'the drill head blades and thereby holding said blades in the head.

Other objects, advantages and, features or in vention may appear from the accompanying drawing, the subjoined detailed description and the appended claim. Q

In the drawing: c

Figure 1' is a top plan view of my drill head.

. Figure 2 is a side elevation of the same.

Figure 3-is a side elevation of one of the blades,

showing one type thereof.

Figure 4 is a side elevation of another type of blade.

and the outer end of the drill stem is threaded into'the lower end of a bore l in the chuck. The chuck is also provided with a plurality of radialgrooves 5, which intersect the central bore 4. The radial grooves l are each adapted to receive a cutter blade I. The cutter blades 5 are multisaid recesses being oppositely arranged on each of the blades. The chuck I is provided with shoulders 8, which engage the recesses I, as shown in Figure 2, thus holding the blades 6 against outward movementin the chuck. As

. Figure 5 is an end view of one 01 the blades, a

as shown in Figure 4.

Figure 6 is a plan view of the chuck. I

Figure 7 is a plan view or one form of blade holder.

Figure 8 is a plan view of another type of blade holder. h

Figure 9 is a side elevation of thetype of blade holder as'shown in Figure 7.

Referring more particularly to the drawing, the numeral I' indicates the chuck forming part or the drill head, and this chuck is substantially cylindrical in form. The chuck is provided with longitudinal grooves 2 to permit passage of the water and material, which moves past the drill head in the usual and well-known manner.

A shank or drill stem 3 extends from the drillthan the outer edge of the blades.

shown in Figures 1 and 2, a sharp edge of each of the blades is presented to the surface to be cut, and these blades can be turned end for end, as well as reversed, thus'providing'a number of positions for each of the blades and enabling the tool to operate for a considerable length of time.

If the gauge of the tool decreases, the cutter blades 6 are turned end for end, thus bringing the gauge 0! the tool out to the original dimension, and if the cutting edges become worn, the blades are reversed, thus presenting a new cutting edge to the surface tobe drilled.

For the purpose of holding the cutter blades 6 in position in the chuck, I provide a blade holder and lock 9. This blade holder consists of a central hub II, which fits within the bore 4 of the chuck, and a plurality of radial arms 9 I, which are arranged within the grooves i or the chuck. The arms Ii and the hub in are preferably integrally formed as shown. The arms H of the holder are trough-like in cross section so as to receive the lower edge of the blades 6. When the shank 3 is screwed into the chuck I, it will bear against the hub portion I0 01 the blade holder, thus urging the blade holder upwardly, and thereby pressing the blades 6 tightly against the shoulder I, thus holding all of the blades in drilling position in thechuck. The arms H oi. the blade holder are preferably tilted so that the inner portion of the blades is somewhat higher I However, this is ,a detail which varies with the desire or the user.

To limit the outward movement of the blades 6 in the chuck, a'lip i2 is provided on the outer H, which is cut in the cutter blade I, as shownin Figure 3. This notch rests over a projection 1113 engine of any .usual and well-known type, ll shown in Figure .8 in the groove part of the arms I I", and when the blade holder is presse a central bore and a plurality of radial tightly against the blades, the projection l'l fit ting into the notch I3 will effectively hold the blades against movement in the chuck. The

blade holder 9' shown in Figure 8 is formed with a hub III, the purpose of this hub being the same as the hub 10.

v To adjust or replace the blades 6 in the chuck, it is only necessary to loosen the drill stem 3,

whereupon the blade holder 9 will drop downwardly a small amount suflicient to permit each of. the blades 6 to be slid longitudinally out of the chuck and thereafter adjusted as desired.

Having described my invention, I claim:

A drill head comprising a chuck, said chuck 15 Q "g"rooves extending from the bore, a drill stem" threaded into the bore, each or said grooves being adapted to receive a blade, shoulders on'the chuck engaging each of the blades, a blade holder including a plurality of arms, each of the arms eirtending into a groove, each or said arms bearing against the bottom of a blade, said drill stem bearing against the blade holder and pressing said holder against the blades, means on each of the arms engageable by a blade whereby radial movement of the blade in the chuck is prevented,

said means comprising a projection on each of 

